The invention concerns a filter element for a liquid medium, in particular diesel fuel, that comprises an annularly arranged filter medium that can be flowed through by the liquid medium in a flow direction radial to a longitudinal axis of the filter element; a clean chamber which is arranged in flow direction downstream of the filter medium and which is fluidically connected with an outlet of the filter element for the filtered liquid medium; a cylinder-shaped water separating screen arranged in the clean chamber for separating water contained in the liquid medium; and a water outlet opening by means of which the clean chamber can be fluidically connected to a water collecting chamber of a filter housing. The invention also concerns a filter system with such a filter element.
DE 10 2009 058 812 A1 discloses a fuel filter system with a filter housing and with a filter element arranged in the filter housing in which the filter element comprises an annularly arranged filter medium that can be flowed through by the fuel in a flow direction which is radial to the longitudinal axis of the filter element. The filter element has a clean chamber that is arranged in the interior of the filter element in the flow direction downstream of the filter element. The clean chamber is connected with an outlet of the filter element for the filtered liquid medium. A water separating device with a water separating screen and with a coalescing element which is arranged upstream of the water separating screen in the flow direction serves for separating water from the fuel that is being passed through the filter medium. The clean chamber is fluidically connected by means of a water outlet opening with a water collecting chamber of the filter housing arranged at the bottom.
When exchanging an aforementioned filter element, it must be removed from the filter housing. In this context, contaminants, which during operational use of the filter element have been retained on the exterior of the filter medium and optionally adhere externally to the filter medium, or unfiltered liquid medium may penetrate into the water collecting chamber of the filter housing. The contaminants contained in the water collecting chamber, in particular particles, may be entrained through the water outlet opening (retrograde) into the clean chamber of the filter element after an exchange of the filter element because the clean chamber, in operation of the filter system, is fluidically connected with the separating chamber of the filter element. Such contaminants may cause damage on a machine operated with the liquid medium, for example, an internal combustion engine.